A number of automatic ticket gates are arranged at a railway station. Insertion of a ticket, pass or prepaid card into such an automatic ticket gate opens a door arranged at an end of the ticket gate or doors disposed at opposite ends of the ticket gate (only one door will hereinafter be referred to for the sake of brevity in description) so that boarding of a train without a valid ticket, pass or prepaid card can be prevented.
The door for the ticket gate is obviously required to be equipped not only with sufficient strength but also with safety to passengers, so that a metal plate as a core material is covered at a surface thereof with a cushioning material of substantial thickness. This metal plate may hereinafter be called “an iron plate” as a typical example. It has been a conventional practice to use polyurethane foam as such a cushioning material. As polyurethane resin is high in specific gravity and the cushioning material is required to have a certain degree of strength, the polyurethane foam has a low expansion ratio and as a consequence, the door becomes heavy. This door is opened and closed in accordance with magnetic information inputted in each ticket or the like and, when a prepaid card is used, the door is operated in association with a printer which serves to print a boarding record on the prepaid card. Since the door arranged at the ticket gate with such complex structures built therein as described above is heavy, the equipment in the ticket gate are often caused to develop troubles due to impacts exerted upon opening and closure of the door, resulting in a substantial cost for their repair.
The conventional door making use of polyurethane foam as a cushioning material is fabricated by providing an iron plate as a core material, placing the core material in a casting mold, and injecting two-pack urethane components into the mold and then forming polyurethane foam within the mold. The iron plate as the core material is provided with several through-holes to reduce its weight and also to fix the cushioning material thereon. The reacted polyurethane foam is firmly bonded on the surface of the iron plate, and further, fills up the through-holes of the iron plate. When the door is damaged or stained or otherwise becomes no longer suited for continued use and is replaced by a new door, it is desired to recycle the iron plate of the replaced door. In practice, however, its is extremely difficult to separate the iron plate and the polyurethane foam from each other because they are integrated together as described above. The door so replaced is, therefore, disposed of by land filling or the like, and no recycling has been materialized for the iron plate and polyurethane foam which are both valuable resources.